SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf98194b34b37c5775a8e00872304ce809c78dba432cb359fc258d506fa0fd63' 
  AND token = 'ssWTRRHQS8jQfyhkZ1+Qo1NffwpjauOoHhm8hsmd1uo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}